.NET Essentials: LINQ for Databases

Learn how to use Microsoft LINQ to simplify working with databases. Explore the LINQPad code editor, queryable types, basic query syntax, finding data by date range, and more.

Introduction

• Query your database data with LINQ
• What you should know
• How to access the sample code on GitHub
• Why this course uses LINQPad
• Install LINQPad

1. Get Started

• Understand LINQ for Databases
• Examine the Entity Framework sample
• Use the EF models in an application
• Quick look at how to create EF models

2. Databases and LINQPad

• Connect to included sample database
• Connect to another database
• Connect to EF model in a .NET assembly
• View the database structures in LINQPad

3. Explore Queryable Types

• Explore the relevant LINQ types
• Understand the DbContext
• Queryable types: DbSet and DbQuery
• DbSet, the basis for EF collection models
• Save changes in DbSet
• DbQuery, the basis of LINQ queries for EF models
• Interfaces: IEnumerable and IQueryable
• View the Expression Tree
• View the generated SQL

4. Basic Query Syntax

• Basic concepts of LINQ
• Enumerable and Queryable extension methods
• Use extension methods syntax
• Use query expression syntax

5. Fun with Queries

• Projection, get fewer columns
• Paging with Take and Skip
• Use Find for faster search by key
• Use EF navigation properties instead of joins
• Use the Contains method for
• Organize query results into groups with GroupBy
• Flatten child collections with SelectMany
• Find data within a date range

Conclusion

• Next steps